Method for cutting liquid crystal display panel and method for fabricating liquid crystal display panel using the same

ABSTRACT

A method for cutting a liquid crystal display panel includes transferring a pair of mother substrates on which a plurality of panel regions have been disposed to a scribing unit; forming first and second prearranged cut lines on front and rear surfaces of the mother substrates using a scribing unit; transferring the mother substrates with the first and second prearranged cut lines formed thereon to a breaking component; and moving a transfer unit which includes a body having a plurality of suction members and a steam generator installed at an edge of the body to an upper side of the mother substrates, and separating liquid crystal display panels formed at the panel regions from a dummy glass therearound while spraying steam onto the surface of the mother substrates through the steam generator of the transfer unit.

This application claims the benefit of Korean Patent Application No.10-2005-134431, filed on Dec. 29, 2005, which is hereby incorporated byreference for all purposes as if filly set forth herein. Thisapplication incorporates by reference co-pending application, Ser. No.10/184,096, filed on Jun. 28, 2002 entitled “SYSTEM AND METHOD FORMANUFACTURING LIQUID CRYSTAL DISPLAY DEVICES FROM LARGE MOTHER SUBSTRATEPANELS”; and application, Ser. No. 11/467,919, now U.S. Pat. No.7,450,213 filed on Jun. 29, 2006, entitled “METHODS OF MANUFACTURINGLIQUID CRYSTAL DISPLAY DEVICES” for all purposes as if fully set forthherein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method for cutting a liquid crystaldisplay panel and more particularly, to a method for cutting a liquidcrystal panel to cut a plurality of liquid crystal display panel formedon large-scale mother substrates into a plurality of unit liquid crystaldisplay panels, and a method for fabricating a liquid crystal displaypanel using the same.

2. Discussion of the Related Art

As consumer interest in information displays has grown and the demandfor portable (mobile) information devices has increased, research andcommercialization of light and thin flat panel displays (“FPD”) has alsoincreased. Flat panel displays may be substituted for a Cathode Ray Tube(“CRT”), which is the most common existing display device.

The liquid crystal display (“LCD”) is a FPD device for displaying imagesby using optical anisotropy of liquid crystal. LCD devices exhibitexcellent resolution and color and picture quality and as a result arewidely employed in notebook computers, desktop monitors, and the like.

The typical LCD device includes a liquid crystal display panel includinga driving circuit unit, a backlight unit installed at a lower portion ofthe liquid crystal display panel and emitting light to the liquidcrystal display panel, a mold frame for supporting the backlight unitand the liquid crystal display panel, and a case.

As illustrated in FIG. 1, the liquid crystal display panel 10 includesan image display part 13 in which liquid crystal cells are arranged in amatrix form, a gate pad part 14 connected to gate lines 16 of the imagedisplay part 13 and a data pad part 15 connected to data lines 17 of theimage display part 13.

The gate pad part 14 and the data pad part 15 are formed at an edgeregion of a thin film transistor (TFT) array substrate that does notoverlap with a color filter substrate 2. The gate pad part 14 suppliesscan signals provided from a gate driver (not shown) to the gate lines16 of the image display part 13, and the data pad part 15 supplies imageinformation provided from a data driver (not shown) to the data lines 17of the image display part 13.

Although not shown, the color filter substrate 2 includes a color filterincluding red, green and blue sub-color filters implementing colors, ablack matrix for separating the sub-color filters and blocking lightfrom transmitting through a liquid crystal layer, and a transparentcommon electrode for applying a voltage to the liquid crystal layer.

The array substrate 1 includes a plurality of gate lines 16 and aplurality of data lines 17 arranged vertically and horizontally thereonand defining a plurality of pixel regions; a TFT to be used as aswitching element formed at each crossing of the gate lines 16 and thedata lines 17; and a pixel electrode formed on each pixel region.

The array substrate 1 and the color filter substrate 2 face each otherand are bonded together manner by a seal pattern 40 formed at an edge ofthe image display part 13 to form a liquid crystal display panel 10. Theattachment of the two substrates 1 and 2 with the proper alignment isfacilitated through an alignment key (not shown) formed on one of thearray substrate 1 and the color filter substrate 2.

To improve manufacturing yield the TFT array substrates are formed on alarge-scale mother substrate while the color filter substrates areformed on a separate mother substrate. The two mother substrates arethen bonded together facing each other to form a plurality of liquidcrystal display panels. A cutting process is performed to cut the bondedmother substrates into a plurality of unit liquid crystal displaypanels.

Typically, cutting of the mother substrates is performed by forming aprearranged cut line on the mother substrates using a wheel having ahardness greater than that of glass and then forming and propagating acrack along the prearranged cut line.

FIG. 2 is a view showing the structure of a section of the unit liquidcrystal display panel formed by attaching the first mother substrate onwhich the TFT array substrates are formed to the second mother substrateon which the color filter substrates are formed.

As shown in FIG. 2, in the unit liquid crystal panels, the thin filmtransistor array substrates 1 protrude at one side beyond the colorfilter substrates 2, because the gate pad part and the data pad part areformed at an edge portion of the thin film transistor array substrate 1that does not overlap the color filter substrate 2.

Accordingly, the color filter substrates 2 formed on the second mothersubstrate 30 are separated by first dummy regions 31 each having a widthcorresponding to the protruding portion of the thin film transistorarray substrates 1 formed on the first mother substrate 20.

The unit liquid crystal panels are typically disposed such that thefirst and the second mother substrates 20 and 30 can be utilized totheir maximum, and though the arrangement differs depending on a modelof the unit liquid crystal display panel, the unit liquid crystal panelsare typically formed to be separated by the width of a second dummyregion 32.

After the first mother substrate 20 having the thin film transistorarray substrates 1 formed thereon and the second mother substrate 30having the color filter substrates 2 formed thereon are attached, thesubstrates are cut into individual liquid crystal panels. During thecutting process, the first dummy region 31 formed at the portion wherethe color filter substrates 2 of the second mother substrate 30 areseparated and the second dummy region 32 separating the unit liquidcrystal panels are simultaneously removed.

A related art cutting process for manufacturing the liquid crystaldisplay panel will be described hereinafter with reference to FIG. 3.

FIG. 3 is a view showing a cutting process of the liquid crystal displaypanel of the related art.

As shown, a cutting device of the liquid crystal display panel includesa table 42 on which the bonded first and second mother substrates 20 and30 are loaded, and a cutting wheel 55 for processing the first andsecond mother substrates 20 and 30 to form prearranged cut lines 51.

When using the cutting device of the related art, after the bonded firstand second mother substrates 20 and 30 having a plurality of liquidcrystal display panels are loaded on the table 42, the cutting wheel 55positioned at an upper side of the first and second mother substrates 20and 30 is lowered and rotated to apply a certain pressure against thesecond mother substrate 30 to form prearranged cut lines 51 or grooveson the surface of the second mother substrate 30.

The prearranged cut lines are also formed on the first mother substrate20. The first mother substrate 20 is processed with the cutting wheel 55to form prearranged cut lines at the same positions as the prearrangedcut lines 51 of the second mother substrate 30. Accordingly, in theliquid crystal panel cutting process of the related art, since the firstand second mother substrates 20 and 30 are to be processed to formcorresponding prearranged cut lines, after the second mother substrate30 is processed with the cutting wheel 55, the liquid crystal panel isreversed to have the first mother substrate 20 face upward and the firstmother substrate 20 is processed with the cutting wheel 55.

Thereafter, pressure is applied to the prearranged cut lines 51 formedon the first and second mother substrates 20 and 30 to separate thefirst and second mother substrates 20 and 30 along the prearranged cutlines 51. The first and second mother substrates 20 and 30 are separatedby striking the first and second mother substrates 20 and 30 with abreaking bar to make and propagate a crack along the prearranged cutlines 51.

In cutting the liquid crystal display panel, a scribing process and abreaking process are performed several times through a plurality ofreversals and positionings of the substrates 20 and 30. The significantamount of time used for the scribing process and the breaking processreduces productivity of the overall manufacturing process.

In addition since the mother substrates are struck with the breaking barto make cracks along the prearranged cut lines formed on the mothersubstrates, a plurality of glass chips are generated. Further, if thestriking is performed inaccurately or if crack propagation isincomplete, the liquid crystal display panel may be damaged or torn offwhen it is extracted.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a method for cuttingliquid crystal display panel and method for fabricating liquid crystaldisplay panel using the same that substantially obviates one or more ofthe problems due to limitations and disadvantages of the related art.

Therefore, one aspect of the present invention involves the recognitionby the present inventors of the drawbacks in the related art asexplained above.

An advantage of the present invention is to provide a method for cuttinga liquid crystal display panel capable of shortening time required forcutting a liquid crystal display panel, and a method for fabricating aliquid crystal display panel using the same.

Another advantage of the present invention is to provide a method forcutting a liquid crystal display panel capable of extracting a liquidcrystal display panel from a large-scale mother substrate withoutdamage, and a method for fabricating a liquid crystal display panelusing the same.

Additional features and advantages of the invention will be set forth inthe description which follows, and in part will be apparent from thedescription, or may be learned by practice of the invention. Theobjectives and other advantages of the invention will be realized andattained by the structure particularly pointed out in the writtendescription and claims hereof as well as the appended drawings.

To achieve these and other advantages and in accordance with the purposeof the present invention, as embodied and broadly described, anapparatus for transferring a liquid crystal display panel including: abody having a plurality of suction members; and a steam generatorinstalled at an edge of the body to spray steam toward a mothersubstrate.

In another aspect of the present invention, a method for cutting aliquid crystal display panel includes: transferring a pair of mothersubstrates on which a plurality of panel regions has been disposed to ascribing unit; forming first and second prearranged cut lines on frontand rear surfaces of the mother substrates using a scribing unit;transferring the mother substrates with the first and second prearrangedcut lines formed thereon to a breaking component; and moving a transferunit which includes a body having a plurality of suction members and asteam generator installed at an edge of the body to an upper side of themother substrates, and separating liquid crystal display panels formedat the panel regions from a dummy glass therearound while spraying steamonto the surface of the mother substrates through the steam generator ofthe transfer unit.

In another aspect of the present invention, a method for fabricating aliquid crystal display panel includes: providing mother substratesdivided into a plurality of panel regions; performing an array processon the mother substrate for an array substrate and performing a colorfilter process on the mother substrate for a color filter substrate;forming an alignment film on the surface of the mother substrates;performing rubbing on the alignment film-formed mother substrates;attaching the pair of rubbing-finished mother substrates; forming firstand second prearranged cut lines on front and rear surfaces of theattached mother substrates; and moving a transfer unit which includes abody having a plurality of adsorption members and a steam generatorinstalled at an edge of the body onto the mother substrates, andseparating liquid crystal display panels formed at the panel regionsfrom a dummy glass therearound while spraying steam onto the surface ofthe mother substrates through the steam generator of the transfer unit.

The foregoing and other objects, features, aspects and advantages of thepresent invention will become more apparent from the following detaileddescription of the present invention when taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention.

In the drawings:

FIG. 1 is an plan view showing a plane structure of a unit liquidcrystal display panel formed by attaching a thin film transistor (TFT)array substrate and a color filter substrate in a facing manner;

FIG. 2 is a view showing the structure of a section of the unit liquidcrystal display panel formed by attaching the first mother substrate onwhich the TFT array substrates are formed and the second mothersubstrate on which the color filter substrates are formed;

FIG. 3 is a plan view showing a cutting process of a liquid crystaldisplay panel;

FIG. 4 is a plan view showing a cutting process of a liquid crystaldisplay panel in accordance with an embodiment of the present invention;

FIGS. 5A to 5E illustrate a process of sequentially extracting a unitliquid crystal display panel from a mother substrate by using the transhand;

FIG. 6 is a flow chart illustrating the sequence of processes of onemethod for fabricating a liquid crystal display panel in accordance withan embodiment the present invention;

FIG. 7 is a flow chart illustrating the sequence of processes of amethod for fabricating a liquid crystal display panel in accordance withanother embodiment the present invention the present invention;

FIG. 8 is a flow chart illustrating the sequence of processes of amethod for cutting a liquid crystal display panel in FIGS. 6 and 7 inaccordance with a first embodiment of the present invention; and

FIG. 9 is a flow chart illustrating the sequence of processes of amethod for cutting a liquid crystal display panel in FIGS. 6 and 7 inaccordance with a second embodiment of the present invention.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Reference will now be made in detail to embodiment of the presentinvention, examples of which are illustrated in the accompanyingdrawings.

FIG. 4 is a plan view showing a cutting process of a liquid crystaldisplay panel in accordance with a first embodiment of the presentinvention.

As shown in FIG. 4, a pair of bonded mother substrates 101 on which aplurality of panel regions 111 have been arranged are transferred to ascribing component through a conveying unit to be divided intoindividual unit liquid crystal display panels 110 along the panelregions 111.

The panel regions 111 may comprise upper panel regions and lower panelregions. The upper panel regions 111 can be array substrate on whichthin film transistors (TFTs) have been formed through an array process,and the lower panel region 111 can be a color filter substrate on whichcolor filters have been formed through a color filter process. In theillustrated embodiment of the present invention, the panel regions 111have the same size, but the present invention is not limited thereto andthe panel regions 111 can be formed to have at least two different sizeswith the upper array substrate and the lower color filter substratebonded together to form a unit liquid crystal display panel 110.

In the FIG. 4, the conveying unit is illustrated as including aplurality of conveyer belts 170, but the present invention is notlimited thereto and the conveying unit may alternatively include aplurality of transfer rollers. In addition, the conveying unit mayinclude a first conveying component formed as a conveyer belt coupled toa second conveying component formed as a transfer roller.

After the mother substrates 101 are transferred to the scribingcomponent, first prearranged cut lines 151 are formed to section thepanel regions 111 on the front and rear surfaces of the mothersubstrates 101 in a first direction using a scribing unit 180.

The scribing unit 180 is driven along an X-axis direction. The scribingunit 180 includes a pair of scribing heads (not shown) and repeatedly(e.g. four times) performs a first scribing process to form the firstprearranged cut lines 151 in the first direction, (along the X-axisdirection) on the mother substrates 101 using the scribing heads.

After the first scribing process in the first direction is complete, asecond scribing process is initiated. In the second scribing process,the scribing unit 180 is maintained at a certain position with respectto an X-axis and the heads of the scribing unit 180 are driven in aY-axis direction to form second prearranged cut lines 152 for sectioningthe panel regions 111 on the front and rear surfaces of the mothersubstrates 101 in a second direction. To form the second prearranged cutlines 152 on the mother substrates 101 through the scribing heads, thescribing along the Y-axis direction is repeated eight times.

In this above described example using the embodiment of the presentinvention illustrated in FIG. 4, the first scribing process is performedfour times in the X-axis direction and the second scribing process isperformed eight times in the Y-axis direction to form the total eightsheets of liquid crystal display panels 110 on the large-scale mothersubstrates 101, but the present invention is not limited thereto and thefirst and second scribing process may include any number of repetitionsof scribing in the X and Y axes directions.

The scribing unit 180 includes scribing heads formed at the upper andlower portions thereof to scribe the first and second prearranged cutlines 151 and 152 on the front and rear surfaces of the mothersubstrates 101, and a scribing wheel made of a material having a greaterhardness than that of glass is mounted at each scribing head.

After the scribing process including scribing in the first and seconddirections is complete, the mother substrate 101 is moved to thebreaking component where a breaking process is performed. In thebreaking component, steam is sprayed onto the front and rear surfaces ofthe mother substrates 101 through a steam break 190 disposedsubstantially perpendicular to a proceeding direction of the mothersubstrates 101 to create an propagate a crack along the prearranged cutlines 151 and 152 to thereby separate the liquid crystal display panels110.

The steam break 190 includes a body for receiving water through a watersupply pipe; a heating unit provided inside the body to heat watersupplied through the water supply pipe to generate steam; and a sprayingunit for spraying steam generated by the heating unit onto the surfaceof the mother substrates 101.

Steam generated by the spraying unit is sprayed onto the front and rearsurfaces of the mother substrates 101 at a temperature of about 100° C.to about 250° C. to expand the mother substrates 101 made of the glassmaterial through heat and pressure. The portions where the first andsecond prearranged cut lines 151 and 152 of the mother substrates 101are formed are expanded to make and propagate cracks along the first andsecond prearranged cut lines 151 and 152 to separate the liquid crystaldisplay panels.

An air knife 195 for spraying dried air with a certain pressure isinstalled at a rear surface of the steam break 190 to remove moisture orglass chips remaining on the surface of the mother substrates 101 afterthe steam is sprayed on the mother substrates 101 and to furtherpropagate the cracks formed along the first and second prearranged cutlines 151 and 152.

As stated above, according to the method for cutting the liquid crystaldisplay panel in the first embodiment of the present invention, thefirst prearranged cut lines 151 are formed simultaneously on the frontand rear surfaces of the mother substrates 101 and then the scribingheads are driven in the Y-axis direction to simultaneously form thesecond prearranged cut lines 152 on the front and rear surfaces of themother substrates 101. Thus, without having to rotate or reverse themother substrates 101, the first and second prearranged cut lines 151and 152 can be formed on both the front and rear surfaces of the mothersubstrates 101.

In addition, once the first and second prearranged cut lines 151 and 152have been formed, a crack is formed along the first and secondprearranged cut lines 151 and 152 by using the steam break 190 and theair knife 195 to separate the unit liquid crystal display panels 110.Thus, compared with the breaking process performed by striking using thebreak bar, the process time can be shortened. Further, the damage to theliquid crystal display panels associated with the striking process ofthe related art may be prevented.

The unit liquid crystal display panels 110 once separated from themother substrates 101 through the scribing process and the breakingprocess are extracted through a transfer unit such as a trans hand 160(shown in FIG. 5A) and transferred to an apparatus for carrying out asubsequent processing such as a reversing unit.

In addition to performing the role of extracting the liquid crystaldisplay panels 110 from the mother substrates 101 and transferring themto the reversing unit, the trans hand 160 also serves to furtherpropagate the cracks formed along the first and second prearranged cutlines 151 and 152 to completely separate any dummy glass around theliquid crystal panels 110 from the liquid crystal display panels 110through a breaking process.

A stream generator with a certain form is attached at an edge of thetrans hand 160 to spray stream to the prearranged cut lines 151 and 152before the liquid crystal display panels 110 are extracted to makeand/or further propagate the cracks along the prearranged cut lines 151and 152. The steam generator may have a form corresponding to the shapeof a liquid crystal display panel. Alternatively, the steam generatormay have a circular or rectangular shape. Damage to the liquid crystaldisplay panel 110 due to incomplete separation from the dummy area glasscan be prevented by removing the dummy glass by using a pusher asdescribed below with reference to FIGS. 5A to 5E.

FIGS. 5A to 5E are exemplary views showing a process of sequentiallyextracting a unit liquid crystal display panel from a mother substrateby using the trans hand including a second breaking process using thetrans hand.

As shown in FIG. 5A, after the scribing process and the first breakingprocess are finished, the trans hand 160 is moved to be positioned abovethe liquid crystal display panel 110.

A body 165 of the trans hand 160 includes a plurality of suction members166, to which each liquid crystal display panel 110 is affixed to allowseparation and extraction from the mother substrate. The suction membersmay include suction cups.

Steam generators 164 having a certain form are formed at an edge of thebody 165 of the trans hand 160. In this case, a plurality of steamgenerators 164 can be formed along the edge of the body 165 of the transhand 160, and they can be formed as a single connected rectangular form.The steam generator 164 can be installed at the trans hand 160 such thatit can be positioned near the prearranged cut line 150 where the lowerliquid crystal display panel 110 and the dummy glass 112 contact witheach other, or can be controlling its position within the trans hand160.

Pushers 163 for applying a pushing force to the dummy glass 112 areinstalled at an outer side of the steam generator 164. The push from thepushers removes dummy glass 112 not previously completely separated fromthe liquid crystal display panel 110.

The trans hand 160 is moved downward to be close to the surface of theliquid crystal display panel 110 to be extracted.

As shown in FIG. 5B, while spraying steam toward the prearranged cutline 150 through the steam generator 164 of the trans hand 160, thetrans hand 160 nears the surface of the liquid crystal display panel110.

As shown in FIG. 5C, with the trans hand 160 in contact with the surfaceof the liquid crystal display panel 110, the suction members 166 of thetrans hand 160 are vacuum affixed onto the surface of the liquid crystaldisplay panel 110.

The spraying of steam through the steam generator 164 is maintained fora certain pre-set time to further make and propagate cracks along theprearranged cut lines 150 to separate the dummy glass 112 from theliquid crystal display panel 110.

Thereafter, as shown in FIG. 5D, the trans hand 160 is moved upward andthe liquid crystal display panel 110 affixed on the suction members 166of the trans hand 160 is separated from the dummy glass 112 and movedtogether with the trans hand 160. Since the pushers 163 are installed atthe edge of the trans hand 160 and substantially at the outer side ofthe steam generator 164, although a portion of the dummy glass 112around the liquid crystal display panel 110 may not been separated fromthe liquid crystal display panel 110, a portion of the dummy glass 112which has not yet been separated can be pushed down by the pushers 163to be completely separated from the liquid crystal display panel 110.

After the liquid crystal display panel 110 and the dummy glass 112 arecompletely separated, as shown in FIG. 5E, the trans hand 160 is drivenupward to transfer the liquid crystal display panel 110 affixed onto thesuction members 166 to the reversing unit, with the separated dummyglass 112 remaining on a conveyer belt.

As described above by spraying steam toward the prearranged cut lines150, cracks can be formed and/or propagated along the prearranged cutlines 150 and the dummy glass 112 can be completely separated from theliquid crystal display panel 110. As a result, when the liquid crystaldisplay panel 110 is extracted, damage to and tearing apart of theliquid crystal display panel may be avoided.

In the above-described embodiment of the present invention, a firstbreaking process is performed by using the steam break 190 and the airknife 195, after which a second breaking process is performed by usingthe steam generator 164 of the trans hand 160. However, the presentinvention is not to this sequence of operations, and if the cracks aresufficiently formed at the prearranged cut lines 150 by the steamgenerator 164 of the trans hand 160, the first breaking process can beomitted and the breaking process by using the steam generator 164 can beperformed without the first breaking process.

FIG. 6 is a flow chart illustrating the processes of one method forfabricating a liquid crystal display panel in accordance with thepresent invention, and FIG. 7 is a flow chart illustrating the processesof another method for fabricating a liquid crystal display panel inaccordance with the present invention.

Specifically, FIG. 6 shows a method for fabricating an LCD in which aliquid crystal layer is formed by a liquid crystal injection method, andFIG. 7 shows a method for fabricating an LCD in which a liquid crystallayer is formed by a liquid crystal dropping method.

The process for fabricating the liquid crystal display panel can bedivided into a switching device array process for forming a switchingdevice on the lower array substrates; a color filter process for forminga color filter on the upper color filter substrate; and a cell processfor attaching the array substrate and the color filter substrate.

In the switching device array process, a plurality of gate lines and aplurality of data lines arranged to define pixel regions on the lowersubstrate are formed and a TFT, a switching device, is formed to beconnected to the gate lines and the data lines at each of the pixelregions (step S101). In addition, a pixel electrode connected to the TFTto drive the liquid crystal layer using a signal applied thereto throughthe TFT is formed through the switching device array process.

A color filter layer comprising red, green and blue sub-color filtersimplementing color and a common electrode may be formed on the uppersubstrate through the color filter process (step S103).

When an in-plane switching (IPS) mode LCD device is being fabricated,common electrodes are instead formed on the lower substrate on which thepixel electrodes have been formed through the array process.

Subsequently, an alignment film is printed on the upper and lowersubstrates. A rubbing process is performed on the alignment film on eachsubstrate to establish an anchoring force or a surface fixing force toestablish the initial alignment (i.e., a pretilt angle and an alignmentdirection) for liquid crystal molecules of a liquid crystal layer formedbetween the upper and lower substrates (step S102 and S104).

After the rubbing process is finished, the upper and lower substratesare inspected as to determine whether the alignment films are defectiveusing an alignment film inspecting device (step S105).

The liquid crystal display panel uses electro-optic effects of liquidcrystal, and since the electric optical effect is determined byanisotropy of the liquid crystal itself and a state of arrangement ofliquid crystal molecules, controlling of the arrangement of liquidcrystal molecules greatly influences the stabilization of displayquality of the liquid crystal display panel.

Accordingly, the alignment film forming process for establishing theinitial aligning of the liquid crystal molecules is of great importancewith respect to establishing the picture quality in a liquid crystaldisplay panel.

A method for inspecting for a rubbing deficiency includes a firstinspecting process to detect whether the coated alignment film has ablur, a strip or a pin hole on its surface, and a second inspectingprocess to detect non-uniformities in the surface of the rubbedalignment film and to detect whether the surface of the alignment filmis scratched are performed.

After the inspection of the alignment film is completed, as shown inFIG. 6, spacers for uniformly maintaining a cell gap are formed on thelower substrate and a sealant is coated on an outer edge of the uppersubstrate. The lower and upper substrates are attached or bonded byapplying a pressure thereto (steps S106˜S108). The spacers can be ballspacers dispersed according to a spreading method, or can be columnarspacers formed through patterning.

The lower and upper substrates are formed as large-scale glasssubstrates or mother substrates. A plurality of panel regions are formedon the large-scale glass substrates, and the TFT, the switching device,and the color filter layer are formed at each panel region. The glasssubstrates are cut and processed to separate the mother substrates intoindividual liquid crystal panels (step S109).

Methods for cutting a liquid crystal display panel in accordance withembodiments of the present invention to separate the mother substratesinto individual liquid crystal panels will now be described in detailwith reference to FIGS. 8 and 9.

FIG. 8 is a flow chart illustrating a sequence of processes of a methodfor cutting a liquid crystal display panel in FIGS. 6 and 7 inaccordance with a first embodiment of the present invention, and FIG. 9is a flow chart illustrating a sequence of processes of a method forcutting a liquid crystal display panel in FIGS. 6 and 7 in accordancewith a second embodiment of the present invention.

Specifically, FIG. 8 shows a method for cutting a liquid crystal displaypanel in which the first breaking process is performed by using thesteam breaker and the air knife and the second breaking process isperformed by using the steam generator attached at the trans hand, andFIG. 9 shows an example of a method for cutting the liquid crystaldisplay panel in which the breaking process and the extracting processare performed together by using the steam generator attached at thetrans hand.

First, the pair of bonded mother substrates on which the plurality ofpanel regions has been formed are loaded and transferred to the firstscribing component through the transfer unit (steps S201 and S301). TheTFT switching elements and the color filters have been formed on theupper and lower panel regions. The upper and lower panel regions havebeen bonded together to form liquid crystal display panels.

After being transferred to the scribing component, the first prearrangedcut lines are formed to section the panel regions in the first directionand the second prearranged cut lines are formed to section the panelregions in the second direction on the front and rear surfaces of themother substrates using the first scribing unit (steps S202 and S302).

After the scribing process including scribing in the first and seconddirections is complete, the mother substrates are moved to the breakingcomponent in which steam and dry air are sprayed onto the front and rearsurfaces of the mother substrates through the steam break and the airknife (the breaking units) during the first breaking process to formcracks along the prearranged cut lines (step S203).

After the scribing process and the first breaking process are completedon the mother substrates, the trans hand is moved to a position above aliquid crystal display panel to be extracted (steps S204-1 and S303-1).

Step S204 of FIG. 8 shows the case in which after the first breakingprocess is performed by using the steam break and the air knife and thesecond breaking process is performed by using the trans hand, while stepS303 of FIG. 9 shows the case in which the first breaking process isomitted and only the second breaking process is performed by using thetrans hand.

Thereafter, the trans hand is moved downward to approach the surface ofthe liquid crystal display panel to be extracted. While steam is beingsprayed toward the prearranged cut lines through the steam generator ofthe trans hand, the trans hand contacts the liquid crystal display panel(steps S204-2 and S303-2).

With the trans hand in contact with the surface of the liquid crystaldisplay panel, the suction members of the trans hand are affixed ontothe surface of the liquid crystal display panel to be extracted.

Steam spraying through the steam generator is maintained for a certainpre-set time to create and propagate cracks formed along the prearrangedcut lines to allow the dummy glass to be separated from the liquidcrystal display panel (steps S204-3 and S303-3).

Thereafter the trans hand is moved upward and the liquid crystal displaypanel affixed onto the suction members of the trans hand is separatedfrom the dummy glass and moved upward together with the trans hand. If aportion of the dummy glass has not been separated from the liquidcrystal display panel, the non-separated portion of the dummy glass canbe physically removed by using the pusher installed at an outer edge ofthe trans hand to completely remove the dummy glass from the liquidcrystal display panel (steps S204-4 and S303-4).

Thereafter, as shown in FIG. 6, liquid crystal may be injected through aliquid crystal injection opening of each unit liquid crystal displaypanel. After the liquid crystal is injected, the liquid crystalinjection opening is sealed to form a liquid crystal layer, and eachunit liquid crystal display panel is inspected, thereby finishingfabrication of each of the unit liquid crystal display panels (stepsS110 and S111).

The liquid crystal may be injected by using a vacuum injection methodusing a pressure difference. In the vacuum injection method, the liquidcrystal injection opening of the unit liquid crystal display panel isput in a container filled with liquid crystal in a chamber with acertain degree of vacuum. The degree of vacuum is then changed to allowliquid crystal to be injected into the liquid crystal display panelaccording to a pressure difference between the interior and the exteriorof the liquid crystal display panel. When the liquid crystal has filledinside the liquid crystal display panel to form a liquid crystal layer,the liquid crystal injection opening is sealed. As described above, toform the liquid crystal layer of the liquid crystal display panelthrough the vacuum injection method, a portion of a seal pattern is openfor injecting the liquid crystal.

However, the vacuum injection method has the following problems.

First, a relatively long time is used to inject the liquid crystal intothe liquid crystal display panel. Typically, the attached liquid crystaldisplay panel has an area of hundreds of cm² and an opening forinjecting liquid crystal of merely a few μm across. Accordingly, thequantity of liquid crystal injected per unit hour using the vacuuminjection method is inevitably small. For example, about 8 hours arerequired for injecting the liquid crystal to fabricate a 15-inch liquidcrystal display panel. The time required to inject the liquid crystalinto the liquid crystal display panel reduces the overall productivityof the manufacturing process. In addition, as the liquid crystal displaypanel increases in size, the time taken for injecting liquid crystalincreases, and a defective filling of liquid crystal may also occur. Forthese reasons, the vacuum injection method may have limited use whenmanufacturing large liquid crystal display panels.

Secondly, the vacuum injection method uses a large amount of liquidcrystal. Typically, the amount of liquid crystal actually injected intothe liquid crystal display panel is quite small compared with the amountof liquid crystal filled in the container. When liquid crystal isexposed to the air or to certain gases, the liquid crystal reacts withthe air or gas and is degraded. Thus, although the liquid crystal filledin the container is used to fill a plurality of unit liquid crystaldisplay panels, a large amount of the liquid crystal remaining in thecontainer after completing the filling is discarded. Accordingly, theunit cost of the liquid crystal panel is increased, reducing the pricecompetitiveness of the LCD panels.

In order to solve the above-described problems associated with thevacuum injection method a dropping method may be employed to form theliquid crystal layer.

As shown in FIG. 7, when using the dropping method, after the alignmentfilm is inspected (step S105), a certain seal pattern is formed with asealant on the color filter substrate and a liquid crystal layer isformed on the array substrate (steps S106′ and S107′) by dropping theliquid crystal on the large-scale first mother substrate where aplurality of array substrates is disposed. Alternatively, the liquidcrystal may be dropped on an image display region of the second mothersubstrate where the plurality of color filter substrates is disposed.

After liquid crystal is dropped, the first and second mother substratesare bonded by applying a certain pressure thereto to uniformlydistribute the liquid crystal to the entire image display region to forma liquid crystal layer.

Thus, in the case where the liquid crystal layer is formed in the liquidcrystal display panel through the dropping method, the seal pattern isformed as a closed pattern surrounding the outer edge of the pixel partregion to prevent a leakage of liquid crystal to outside of the imagedisplay region.

The dropping method allows forming the liquid crystal layer within arelatively short time compared to the time used by the vacuum injectionmethod and can quickly form the liquid crystal layer even when theliquid crystal display panel is large.

In addition, since only the desired amount of liquid crystal is droppedon the substrate, an increase in the unit cost of the liquid crystaldisplay panel due to discarding the high-priced liquid crystal can beprevented enhancing the price competitiveness of the LCD panels.

After the upper and lower substrates on which liquid crystal has beendropped and the sealant has been coated are aligned, a pressure isapplied thereto to bond the lower and upper substrate together with thesealant and to spread the dropped liquid crystal uniformly on the entireportion of the panel (step S108′).

Through the above described processes, the plurality of liquid crystaldisplay panels with the liquid crystal layer formed thereon are formedon the large-scale glass substrates (upper and lower substrates). Theglass substrates are processed and cut into a plurality of liquidcrystal display panels, which are then inspected to thereby finishfabrication of the liquid crystal display panel (steps S109′ and S110′).

It will be apparent to those skilled in the art that variousmodifications and variation can be made in the present invention withoutdeparting from the spirit or scope of the invention. Thus, it isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

1. A method for cutting a liquid crystal display panel comprising:transferring a pair of mother substrates on which a plurality of panelregions has been disposed to a scribing unit through a convey unit;forming first and second prearranged cut lines on front and rearsurfaces of the mother substrates using a scribing unit; transferringthe mother substrates with the first and second prearranged cut linesformed thereon to a breaking component through the convey unit; moving atransfer unit which includes a body having a plurality of suctionmembers, a steam generator installed at an edge of the body and a pusherinstalled an outer side of the transfer unit to an upper side of themother substrates; moving the transfer unit downward to be close to thesurface of the mother substrates and spraying steam toward the first andsecond prearranged cut lines through the steam generators of thetransfer unit; fixedly adsorbing the surface of the panel regions to beextracted through the adsorption members while the steam sprayingthrough the steam generators are maintained for a certain pre-set timeto further make cracks formed along the first and second prearranged cutlines; moving the transfer unit upward to separate liquid crystaldisplay panels formed at the panel regions from a dummy glasstherearound while spraying steam onto the surface of the mothersubstrates through the steam generator of the transfer unit; andtransferring the liquid crystal display panels absorbed on theabsorption members to a reversing unit with the separated dummy glassremaining on the convey unit.
 2. The method of claim 1, wherein aplurality of steam generators are formed along the edge of the body. 3.The method of claim 1, wherein the steam generator has a formcorresponding to the shape of the liquid crystal display panel.
 4. Themethod of claim 1, the steam generator has a rectangular shape.
 5. Themethod of claim 1, the steam generator has a circular shape.
 6. Themethod of claim 1, wherein forming the first and second prearranged cutlines on the front and rear surfaces of the mother substrates includes:forming the first prearranged cut lines for sectioning the panel regionson the front and rear substrates of the mother substrates in a firstdirection through a scribing unit; and forming the second prearrangedcut lines for sectioning the panel regions on the front and rearsubstrates of the mother substrates in a second direction by driving ahead provided at the scribing unit in a second direction.
 7. The methodof claim 1, wherein forming the first and second prearranged cut linesincludes forming the first and second prearranged cut lines to crosssubstantially perpendicularly.
 8. The method of claim 1, wherein thebreaking component includes a breaking unit installed at the breakingcomponent to form cracks along the first and second prearranged cutlines of the mother substrates.
 9. The method of claim 8, wherein thebreaking unit includes a steam break to spray steam onto the front andrear surfaces of the mother substrates.
 10. The method of claim 9,wherein the breaking unit includes an air knife installed at a rearsurface of the steam break to spray air onto the surface of the mothersubstrate.
 11. The method of claim 8, wherein the steam generator of thetransfer unit is arranged to propagate cracks formed along the first andsecond prearranged cut lines through the breaking unit.
 12. The methodof claim 1, wherein the steam generator of the transfer unit spray steamon the surface of the mother substrates is arranged to expand the mothersubstrates by heat and pressure to thereby form cracks along the firstand second prearranged cut lines or further making formed cracks.
 13. Amethod for fabricating a liquid crystal display panel comprising:providing first and second mother substrates divided into a plurality ofpanel regions; performing an array process on the first mother substratefor an array substrate and performing a color filter process on thesecond mother substrate for a color filter substrate; forming analignment film on the surface of the first and second mother substrates;performing rubbing on the alignment film-formed first and second mothersubstrates; bonding together the first and second rubbing-finishedmother substrates; forming first and second prearranged cut lines onfront and rear surfaces of the bonded mother substrates through ascribing unit; moving a transfer unit which includes a body having aplurality of suction members, a steam generator installed at an edge ofthe body and a pusher installed an outer side of the transfer unit to anupper side of the first and second mother substrates; moving thetransfer unit downward to be close to the surface of the mothersubstrates and spraying steam toward the first and second prearrangedcut lines through the steam generators of the transfer unit; fixedlyadsorbing the surface of the panel regions to be extracted through theadsorption members while the steam spraying through the steam generatorsare maintained for a certain pre-set time to further make cracks formedalong the first and second prearranged cut lines; moving the transferunit upward to separate liquid crystal display panels formed at thepanel regions from a dummy glass therearound while spraying steam onto asurface of the first and second mother substrates through the steamgenerator of the transfer unit; and transferring the liquid crystaldisplay panels absorbed on the absorption members to a reversing unitwith the separated dummy glass remaining on a convey unit.
 14. Themethod of claim 13, wherein forming the first and second prearranged cutlines on the front and rear surfaces of the mother substrates comprises:forming the first prearrange cut lines for sectioning the panel regionson the front and rear substrates of the mother substrates in a firstdirection through a scribing unit; and forming the second prearrange cutlines for sectioning the panel regions on the front and rear substratesof the mother substrates in a second direction by driving a headprovided at the scribing unit in a second direction.
 15. The method ofclaim 13, wherein forming the first and second prearranged cut lines onthe front and rear surfaces of the mother substrates comprises formingthe first and second prearranged cut lines cross substantiallyvertically.
 16. The method of claim 13, further comprising formingcracks along the first and second prearranged cut lines on the mothersubstrates using a breaking unit.
 17. The method of claim 16, whereinthe breaking unit includes a steam break to spray steam onto the frontand rear surfaces of the mother substrates.
 18. The method of claim 17,wherein the breaking unit includes an air knife installed at a rearsurface of the steam break and wherein the method further comprisesspraying air onto the surface of the mother substrates.
 19. The methodof claim 16 further comprising propagating cracks formed along the firstand second prearranged cut lines with the breaking unit using the steamgenerator of the transfer unit.
 20. The method of claim 13, furthercomprising spraying steam using the steam generator of the transfer unitonto the surface of the mother substrates to expand the mothersubstrates by heat and pressure to thereby form cracks along the firstand second prearranged cut lines.
 21. The method of claim 13, furthercomprising spraying steam using the steam generator of the transfer unitonto the surface of the mother substrates to expand the mothersubstrates by heat and pressure to thereby propagate cracks along thefirst and second prearranged cut lines.
 22. The method of claim 13,wherein the panel regions on the upper portion of the bonded mothersubstrates are array substrates on which TFTs have been formed throughthe array process and the panel regions on the lower portion of themother substrates are color filter substrates on which color filtershave been formed through the color filter process.
 23. The method ofclaim 13, wherein the plurality of panel regions includes panel regionshaving at least two different sizes.
 24. The method of claim 13, furthercomprising: dropping liquid crystal on one of the rubbing-finishedmother substrate for the array substrate and the mother substrate forthe color filter substrate; and coating sealant on the other one of therubbing-finished mother substrate for the array substrate and the mothersubstrate for the color filter substrate.
 25. The method of claim 24,wherein bonding together the first and second rubbing-finished mothersubstrates is performed after dropping liquid crystal on one of therubbing-finished mother substrate for the array substrate and the mothersubstrate for the color filter substrate.
 26. The method of claim 13,further comprising: forming spacers on one of the rubbingprocess-finished mother substrate for the array substrate and the mothersubstrate for the color filter substrate; and coating sealant on theother one of the rubbing process-finished mother substrate for the arraysubstrate and the mother substrate for the color filter substrate. 27.The method of claim 26, wherein bonding together the first and secondrubbing-finished mother substrates is performed after forming spacers onone of the rubbing process-finished mother substrate for the arraysubstrate and the mother substrate for the color filter substrate. 28.The method of claim 27, further comprising after separating liquidcrystal display panels formed at the panel regions from a dummy glasstherearound from the bonded mother substrates, injecting liquid crystalinto a separated liquid crystal display panel.